Method and apparatus for processing protection switching mechanism in optical channel shared protection rings

Abstract

A method for merging protection switching messages in an optical network enables a control of the amount of message bandwidth used for sending protection switching messages. A method for performing protection switching in an optical network does so in an optimal manner by performing the protection switching actions in the various nodes of a protection path in parallel rather than in sequence. To do so, a channel failure message is transmitted from an end node A in the optical network upon detecting a failure in a link in the optical network that includes the end node A. If a failure can be detected at both end nodes, the channel failure messages are transmitted from both end nodes the moment they detect failure without any further waiting. Upon receiving the first channel failure message regardless its originating end node, switching actions in intermediate nodes are initiated. The channel failure messages are forwarded from the intermediate nodes to their corresponding next nodes before completing switching actions in the intermediate nodes. When receiving channel failure response messages, these messages are forwarded to a next node from the intermediate node only after switching actions are complete in the intermediate node.

1. A method for processing channel failure response messages in an optical network comprising:
 merging a plurality of channel failure response messages into one combination channel failure response message as long as all of the plurality of channel failure response messages travel in a same direction; 
 determining which of the plurality of channel failure response messages will be included in the combination channel failure response message based on a first channel failure response message of the plurality of channel failure response messages waiting at a head of a queue; and 
 forwarding the combination channel failure response message to a next node only after protection switching actions of corresponding circuits of all other embedded channel failure response messages in the combination channel failure response message are complete. 
 
     
     
       2. The method according to  claim 1 , further comprising forwarding a combination channel failure response message received by an intermediate node to a next node only upon completion of protection switching actions for all embedded circuits. 
     
     
       3. The method according to  claim 1 , further comprising stripping corresponding channel information out of the combination channel failure response message whenever the combination channel failure response message reaches an end node corresponding to the channel information. 
     
     
       4. The method according to  claim 1 , further comprising discarding the combination channel failure response message only after all corresponding end nodes of circuits have received the combination channel failure response message. 
     
     
       5. A method for operating an optical network, which has two end nodes coupled together by one or more intermediate nodes, comprising:
 in response to a bi-directional failure in which both end nodes detect the failure:
 transmitting a channel failure message from at least two nodes in the network in parallel in response to a channel failure detection; 
 performing protection switching actions at two end nodes before transmitting channel failure messages; and 
 performing protection switching actions in a third node in response to receipt of a channel failure message from either of the at least two nodes; 
 
 merging a plurality of channel failure response messages into one combination channel failure response message as long as all of the plurality of channel failure response messages travel in a same direction; 
 determining which of the plurality of channel failure response messages will be included in the combination channel failure response message based on a first channel failure response message of the plurality of channel failure response messages waiting at a head of a queue; and 
 forwarding the combination channel failure response message to a next node only after protection switching actions of corresponding circuits of all other embedded channel failure response messages in the combination channel failure response message are complete. 
 
     
     
       6. The method according to  claim 5 , further comprising transmitting a channel failure response message from one of the at least two nodes upon receipt of the channel failure message from the other of the at least two nodes. 
     
     
       7. The method according to  claim 6 , further comprising forwarding a channel failure response message from the third node only after completing protection switching actions in the third node. 
     
     
       8. The method according to  claim 6 , further comprising switching working traffic to the protection path at one of the at least two nodes upon receipt of the channel failure response message from the other of the at least two nodes.